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Initialize Block

The initialize block sets up the simulation start conditions, including the initial temperature, pressure, velocity and many others. This block is used for all initialization features, whether its to start a cold-flow simulation or ignite a flame.

Warning

This block is mandatory for all simulations.

Flags Overview

Note

All flags and their description are included in the table below. A detailed description of which values are possible for each input flag follows.

Flag Required Description
init_type Yes defines the category of the initial profile for the simulation (list in /SOURCES/INIT/dino_init_sol.f90)
use_compact No enables 6th-order compact difference scheme instead of 6th-order explicit finite difference scheme (under testing due to limited parallel performance)
use_explicit_filter No activates explicit filter with order specified by explicit_filter_order (2, 4, or 8)
explicit_filter_order No sets the order of the explicit filter; effective only if USE_EXPLICIT_FILTER = .TRUE.
reduce_fd_order No reduces the finite-difference order
init_pressure Yes initial thermodynamic pressure
init_temperature Yes initial temperature of the fluid
solid_temperature Yes initial temperature of the wall
init_temp_oxid Yes initial temperature of the oxidizer
init_temp_fuel Yes initial temperature of the fuel
randomseeds No if true, the random number generator seeds are chosen randomly; otherwise fixed
jet_flow_dir No direction of jet flow (x=1, y=2, z=3); only for jet initialization (init_type=32)
init_xvel Yes initial velocity component in x direction
init_yvel Yes initial velocity component in y direction
init_zvel Yes initial velocity component in z direction
init_vel_jet No initial velocity of the jet flow
init_vel_pilot No initial velocity of the pilot flow
init_vel_coflow No initial velocity of the coflow
inflow_bc No activates inflow boundary conditions
radius No radius of the flow
radius_jet No radius of the area of the jet flow
radius_pilot_in No radius of the inlet area of the pilot flow
radius_pilot_out No radius of the outlet area of the pilot flow
radius_coflow No radius of the area of the coflow
stiff No stiffness parameter between the jet flow and the coflow
init_temp_jump No temperature difference between fresh and burnt gas
init_vel_jump No velocity difference between jet and coflow
const_rho No constant density for incompressible flow only
const_mu No constant viscosity for incompressible flow only
gas_phase(1) Yes defines the chemical mechanism file stored in the /WORK/MECHANISMS directory; you can also add new chemistry mechanisms in *.xml format to this directory for use in the simulation
gas_phase(2) Yes defines the fuel stream composition of the gas; used in diffusion flames or as the complete mixture composition in premixed flames
gas_phase(3) Yes defines the oxidizer stream composition of the gas; used in diffusion flames and left empty for premixed flames
equi_ratio No mixture equivalence ratio
species_fuel(1) No first fuel species, only important for visualization and computing flame speed
species_fuel(2) No second fuel species, only important for visualization and computing flame speed
species_prod(1) No first product species, only important for visualization and computing flame speed
species_prod(2) No second product species, only important for visualization and computing flame speed
species_inert(1) No inert species, only important for visualization and computing flame speed

Flags Details

INIT_TYPE

Defines the category of the initial profile for the simulation (list in '/SOURCES/INIT/dino_init_sol.f90')

  • Type: integer
  • Values: 0–57
  • Default: 0

USE_COMPACT
  • Type: boolean
  • Values: .TRUE./.FALSE.
  • Default: .FALSE.
  • Description: enables 6th-order compact difference scheme instead of 6th-order explicit finite difference scheme

USE_EXPLICIT_FILTER
  • Type: boolean
  • Values: .TRUE./.FALSE.
  • Default: .FALSE.
  • Description: activates explicit filter with order specified by explicit_filter_order (2, 4, or 8)

EXPLICIT_FILTER_ORDER
  • Type: integer
  • Values: 2, 4, 8
  • Default: 8
  • Description: sets the order of the explicit filter; effective only if USE_EXPLICIT_FILTER = .TRUE.

REDUCE_FD_ORDER
  • Type: boolean
  • Values: .TRUE./.FALSE.
  • Default: .FALSE.
  • Description: reduces the finite-difference order

INIT_PRESSURE
  • Type: real
  • Values: positive real
  • Default: 101325 Pa
  • Description: initial thermodynamic pressure

INIT_TEMPERATURE
  • Type: real
  • Values: positive real
  • Default: 300 K
  • Description: initial temperature of the fluid

Solid_temperature
  • Type: real
  • Values: positive real
  • Default: 300 K
  • Description: initial temperature of the solid walls, active only in case of IBM active

INIT_TEMP_OXID
  • Type: real
  • Values: positive real
  • Default: 300 K
  • Description: initial temperature of the oxidizer (in case of there are two different streams -fuel and oxidizer streams)

INIT_TEMP_FUEL
  • Type: real
  • Values: positive real
  • Default: 300 K
  • Description: initial temperature of the fuel (in case of there are two different streams -fuel and oxidizer streams)

RANDOMSEEDS
  • Type: boolean
  • Values: .TRUE./.FALSE.
  • Default: .TRUE.
  • Description: if true, the random number generator seeds are chosen randomly; otherwise fixed

JET_FLOW_DIR
  • Type: integer
  • Values: 1, 2, 3
  • Default: 1
  • Description: direction of jet flow (x=1, y=2, z=3); only for jet initialization (init_type=32)

INIT_XVEL
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: initial velocity component in x direction

INIT_YVEL
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: initial velocity component in y direction

INIT_ZVEL
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: initial velocity component in z direction

INIT_VEL_JET
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: initial velocity of the jet flow

INIT_VEL_PILOT
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: initial velocity of the pilot flame

INIT_VEL_COFLOW
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: initial velocity of the coflow

INFLOW_BC
  • Type: boolean
  • Values: .TRUE./.FALSE.
  • Default: .FALSE.
  • Description: activates prescirbed inflow boundary conditions

RADIUS
  • Type: real
  • Values: positive real
  • Default: 0.00025 m
  • Description: radius of prescribed area of flow, circle or sphere solid particles

RADIUS_JET
  • Type: real
  • Values: positive real
  • Default: 0.00075 m
  • Description: radius of the area of the jet flow, used as scond radius in case having annular burner with mulitple jets regions (eg. liquid jet)

RADIUS_PILOT_IN
  • Type: real
  • Values: positive real
  • Default: 0.00075 m
  • Description: radius of the inlet area of the pilot flow

RADIUS_PILOT_OUT
  • Type: real
  • Values: positive real
  • Default: 0.00015 m
  • Description: radius of the outlet area of the pilot flow

RADIOUS_COFLOW
  • Type: real
  • Values: positive real
  • Default: 0.00015 m
  • Description: radius of the area of the coflow

STIFF
  • Type: real
  • Values: positive real
  • Default: 500
  • Description: stiffness parameter between the jet flow and the coflow

INIT_TEMP_JUMP
  • Type: real
  • Values: positive real
  • Default: 0 K
  • Description: temperature difference between fresh and burnt gas

INIT_VEL_JUMP
  • Type: real
  • Values: positive real
  • Default: 0 m/s
  • Description: velocity difference between jet and coflow

CONST_RHO
  • Type: real
  • Values: positive real
  • Default: 997 kg/m³
  • Description: constant density for incompressible flow only

CONST_MU
  • Type: real
  • Values: positive real
  • Default: 0.001 Pa·s
  • Description: constant viscosity for incompressible flow only

GAS_PHASE(1)
  • Type: string
  • Values: file name
  • Default: 'air_cold'
  • Description: defines the chemical mechanism file stored in the /WORK/MECHANISMS directory; you can also add new chemistry mechanisms in *.xml format to this directory for use in the simulation

GAS_PHASE(2)
  • Type: string
  • Values: chemistry name
  • Default: 'O2:1.0, N2:3.762'
  • Description: defines the fuel stream composition of the gas; used in diffusion flames or as the complete mixture composition in premixed flames

GAS_PHASE(3)
  • Type: string
  • Values: chemistry name
  • Default: 'O2:1.0, N2:3.762'
  • Description: defines the oxidizer stream composition of the gas; used in diffusion flames and left empty for premixed flames

EQUI_RATIO
  • Type: real
  • Values: positive real
  • Default: 0
  • Description: mixture equivalence ratio

SPECIES_FUEL(1)
  • Type: string
  • Values: chemical species names
  • Default: O2
  • Description: first fuel species, important for visualization, computing flame speed, and very important in case of liquid spray fuel

SPECIES_FUEL(2)
  • Type: string
  • Values: chemical species names
  • Default: O2
  • Description: second fuel species, computing flame speed, and very important in case of liquid spray fuel with precursor or dual fuel

SPECIES_PROD(1)
  • Type: string
  • Values: chemical species names
  • Default: O2
  • Description: first product species, only important for visualization and computing flame speed

SPECIES_PROD(2)
  • Type: string
  • Values: chemical species names
  • Default: O2
  • Description: second product species, only important for visualization and computing flame speed

SPECIES_INERT(1)
  • Type: string
  • Values: chemical species names
  • Default: N2
  • Description: inert species, only important for visualization and computing flame speed

Example

&NML_INITIALIZE
    INIT_TYPE=0,
    USE_COMPACT=.FALSE.,
    USE_EXPLICIT_FILTER=.false.,
    EXPLICIT_FILTER_ORDER=8,
    REDUCE_FD_ORDER=.false.,
    INIT_PRESSURE=101325.D0,
    INIT_TEMPERATURE=300.D0,
    WALL_TEMPERATURE=300.D0,
    INIT_TEMP_OXID=300,
    INIT_TEMP_FUEL=300,
    RANDOMSEEDS=.true.,
    jet_flow_dir=1,
    init_xvel=0.0D0,
    init_yvel=0.0D0,
    init_zvel=0.0D0,
    init_vel_jet=0.0D0,
    init_vel_pilot=0.D0,
    init_vel_coflow=0.0D0,
    inflow_bc=.false.,
    radius=0.25D-03,
    radius_jet=0.75D-3,
    radius_pilot_in=0.75D-3,
    radius_pilot_out=15.D-3,
    radius_coflow=15.D-3,
    stiff=5.D1,
    init_temp_jump=0.0D3,
    init_vel_jump=0.D0,
    const_rho=0.997D3,
    const_mu=1.D-3,
    gas_phase(1)='air_cold',
    gas_phase(2)='O2:1.0, N2:3.762',
    gas_phase(3)='O2:1.0, N2:3.762',
    equi_ratio=0.0,
    species_fuel(1)='O2',
    species_fuel(2)='O2',
    species_prod(1)='O2',
    species_prod(2)='O2',
    species_inert(1)='N2'
/